Why does heat cause blood pressure to rise?

Heat causes blood vessels to dilate, which can lead to a drop in blood pressure. However, if the body becomes dehydrated due to heat exposure, blood volume decreases, which can cause the heart to pump harder, potentially raising blood pressure. Additionally, heat can stimulate the release of stress hormones, which can also contribute to an increase in blood pressure. Overall, the body's response to heat is complex and can have varying effects on blood pressure depending on individual circumstances.